There exists a multicolor display device described in JP-A-4-246683 (Patent Document 2).
In the above device, lamps 11A to 11F having different colors are disposed on side surfaces of respective ridge lines of a light guide plate 10 as shown in FIG. 21, and these lamps 11A to 11F are driven to be turned on appropriately by a power source 14 through 15 lighting circuits 12A to 12F and a control circuit 13, thereby allowing color lights to be incident into the light guide plate 10 and displaying a display body 15 disposed on the light guide plate 10 in multi-colors.
As the relation between the side surfaces of respective ridge lines of the light guide plate 10 and light emitting colors of the lamps 11A to 11F, lamps of the same color systems are arranged on opposite sides of respective ridge lines of the light guide plate 10. For example, red is used as the light emitting color of the lamps 11A and 11D, blue is used as the light emitting color of the lamps 11B and 11E and green is used as the light emitting color of the lamp 11C and 11F.
According to the above structure, multicolor lights are allowed to be incident into the light guide plate 10 and to be mixed, thereby realizing multicolor display.